The best replacement for reins is reigns.

The best alternatives to reins are rated as following:
★★★★★  reigns
★★  german martingale
★  pessoa
★  running martingale
★  market harborough
★  take the reigns
★  roping reins
★  draw reins
  wrist strap
  western reins
  chambon
  split reins
  martingale
  loop reins
  running reins
  side reins

Your alternative for reins is not listed? Suggest!
Speaking about reins, one probably shouldn't forget about slobber straps.

Other search terms related to reins and their ratings are:
★★★★★ slobber straps
★★ backpack for toddlers
★ rucksack
★ romel
You have in mind a companion for reins and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of reins in all years. Click on graph for more.
reins
reigns
german martingale